Latitude D600 has no video

I found this D600 (actually two of them) in the recycle room at work. We are allowed to pick through the offerings as long as we sign them out. This particular one has no video. The screen is dark (could of been the reason it was tossed). The external monitor does work though. I do have a few panels from other D600's that I have swapped out for the original and all of them are dark as well, so that takes care of the back light or the inverter being bad. Is there anything else I can check to narrow down what the problem is? Could it be a blown diode or perhaps one of the IC chips? I do have a multimeter and a soldering iron and am fairly competent in using them.

I would really like to get this one working as it has a 1.8G P4. The other D600 is a 1.4 Celeron.

Sorry if this problem has been discussed before but I do not see a search function. Is there one?

Thanks

 

It is likely a motherboard is bad unless it has a video card, then it could be that.

 

Do you know if the video is on the motherboard? If so do you know where I might be able to see a picture of the motherboard showing the video section?

 

That laptop had the option for an Ati Mobility Radeon 900, can't tell if it has one or not without looking at it.

 

http://support.dell.com/support/edocs/systems/latd600/sm/sysboard.htm#1000473

 

Hi there!

I didn't think I'd be lucky enough to find another person having the IDENTICAL problem as my laptop.
Its a 600m though, should be pretty much the same, and its display is dead too. I assumed that it would be the inverter/back light and was about to order thoe from ebay. But according to you , that's not the problem?

Please let me know if you had any success in getting yours to work. I don't know which parts to get. Mine works properly with external monitor too. Not sure how it can be the motherboard if everything else works fine. And how can it be the display card if the external monitor is working? I assume the same display electronics drive both the lcd and the external monitors.

 

Hi Stick2It,
There are rare cases where the LCD port that's physically soddered onto the motherboard is bad. This could very well be the case for that particular laptop. If video works on an external monitor, the internal video card is working. There are rare cases where this is true, and yet the video card is still faulty (this is only true if the LCD port is on the video card and not on the motherboard). Did you use the same LCD cable when you swapped screens? If so, it could very well be a bad cable.
As for azerty, there's a very good chance that an LCD screen will resolve your issue. 90% of all video failures are a result of the LCD screen. Can you tell if there is a ghosted image on the screen (even though it's black)? If so, a new screen will definitely resolve the issue.

Hope this helps,
Gabe

 

Thank you for replying Gabez.

I think that basically, both of us are trying to figure out a diagnosis method to identify the failure point. Because if we have to order a new part, we have to know what to get. (screen/inverter/backlight/display card/motherboard)

I gather that inverters fail most often, so was going to buy a known good one to test. But this method is for lack of a good diagnosis.

You said that a faint image means the panel is bad. If I (clueless , I admit) saw that, I would assume its the backlight. No? Or are you saying to replace the screen because the backlight is integrated? Or perhaps I am asking, is there a way to know that its the backlight and not the inverter or screen that is bad?

I did discover one interesting frequency detection method to test inverters on the web, but you need a multimeter which can measure frequency. 50khz or so. But I don't have a good diagnostic for the backlight, without disassembling it completely I guess.

My next task is to take it apart, check cable connection points and look for the faint image.

Also Gabez , is it possible to have onboard-builtin-video + an ATI card , such that if one fails, the other could be driving the external monitor? Or can we definitely rest assured that our video hardware is good?

Appreciate the help GabeZ !

 

Hi Azerty,
The LCD is one whole unit (this includes the LCD, Backlight, and inverter). It would be very difficult to repair any one of those three components. We replace the whole unit if any one of those components fail. As far as the faint image, yes, that would mean that the backlight failed and the LCD (the whole unit) needs to be replaced. Also, if the external monitor port is allowing video, you can safely assume that the video hardware is fine. However, this is not to say that the LCD port isn't damaged (which is very rare).

Gabe

 

success!

It was simply the connector which had popped out! Even the touchpad had stopped working an year ago and I was able to get that fixed with a simple reseating. Phew, what a relief that I don't have to figure out which spares to buy.

Oh and did I mention that this was actually my sister's laptop, and that she's on the west coast, and that I did the repairs from the east coast via webcam, using her as my robotic mechanical arm?

Ah, the wonders of technology!

Thanks again for your kind replies Gabe! Hope this discussion+solution also helps future clueless searchers like me.